This thesis investigates interactions between Pavlovian and instrumental processes. The first chapter provides an evaluation of various theoretical analyses of how these two processes might interact in the context of two types of phenomena: Pavlovian-to-instrumental transfer (PIT) and the renewal of instrumental responses that have been extinguished. It is argued that the conditions under which both phenomena are observed do not sit readily with the theoretical analyses that have been offered for them. Chapter 2 reports three experiments that examined the conditions under which outcome-selective and general PIT occur in rats. Outcome-selective PIT was not increased by procedures that should increase the distinctiveness of the outcomes; but general PIT was more likely to be observed under conditions in which the distinctiveness of the outcomes should be low (Experiments 1-3). Chapter 3 contrasted the standard stimulus-outcome-response analysis of outcome-selective PIT with a novel theoretical analysis based on mediated stimulus-response associations that directly affect test performance (i.e., without the outcome becoming activated during the test). Experiment 4 demonstrated an outcome-selective PIT effect when the outcome (O) was embedded in the Pavlovian conditioned stimulus (S), and Experiments 5 and 6 showed that outcome-selective PIT was more likely to be observed after backward pairings (i.e., O-S) than after forward pairings (i.e., S-O). These results are consistent with the following analysis: Instrumental training establishes response-outcome and outcome-response associations, and during subsequent backward conditioning the outcome provokes its associated instrumental response during the stimulus and thereby allows a stimulus–response association to be acquired. This stimulus-response association then directly generates outcome-selective PIT at test. Experiment 7 provided direct evidence to support the ix assumptions upon which this analysis relies. These results, together with other paradoxical effects of the Pavlovian relationship, are incongruent with accounts of outcome-selective PIT that rely on a stimulus-outcome-response chain. Chapter 4 explored another instance where Pavlovian stimuli exert a powerful influence on instrumental performance: the case of instrumental renewal. Two fundamental issues were addressed: whether or not direct Pavlovian associations are responsible for the renewal effect, and whether or not renewed responses are controlled by goal-directed processes or stimulus-response associations. In Experiment 8, instrumental renewal was observed without concomitant involvement of any excitatory or inhibitory Pavlovian properties of the contexts involving the outcome; and in Experiment 9, renewed responding was sensitive to the current value of the outcome. Taken together, these results suggest that the extinction context exerts a direct (or hierarchical) inhibitory influence on the instrumental response-outcome association, the removal of which allows the impact of the response-outcome association of performance to be revealed. Chapter 5 explores the broader implications of these results for current theoretical analyses that rely on the idea that Pavlovian and instrumental processes interact through shared access to the features of the outcome.